Here is my experience from today. Keep in mind crowd levels were likely affected by the tropical storm; for days it was forecast to rain all day all weekend (which it did a lot Saturday, and there were tornadoes). This morning it changed to probably raining in the afternoon; by early afternoon there was no chance of rain til the evening. In reality, it sprinkled a bit here and there throughout the day. Not enough for an umbrella but too much for Celestina to come out apparently.
Parking/security/entrance: I have the premier pass and get free prime parking. It was self-park as usual, but less cars than usual. It only took a few minutes to get through the temp check and security. There was no line to get in the park. ID checks have replaced fingerprints. I was past the early entry check at 8:09.
Early entry experience: It was far less crowded than normal. I joined the next group waiting for the Minions preshow. Due to the slower load time, it takes longer to do. I went to Gringotts next. Despite all the social distancing, there was no queue spilling out towards the money exchange. There's a long chained queue set up for the lockers.
General attractions experience: I didn't do everything, but it seems the only preshows running are those for theater attractions. The only exception is FJ- the castle is still "alive" with all the people and talking portraits, but the problem is you mostly get through the room without hearing it all. Every queue has lines on the ground where you are meant to wait til the next one becomes available, but in many spots it is difficult or impossible to see if the next one is clear. No water effects were working. 3D glasses steam up easily; I noticed others having the same problem. I ended up mostly holding the glasses a few inches away from my face. This proved to be very difficult on Transformers and Spiderman because they are so bumpy. You are never seated with another party and there is almost always at least one row between you and the next party. Only once did I see an exception, and I think it's because the kids didn't want to sit together on Hippogriff as they were probably told to.
Masks: Nearly everyone was compliant. In the afternoon I saw some uncovered noses and just a few dangling masks. Employees are telling you to keep them completely on if they see it off, and before every ride. Ride cameras are being monitored; E.T. audio was interrupted for a keep-your-mask-on announcement. I didn't see anyone being told they can't eat/drink and walk. Personally I only did so if no one else was anywhere near me; otherwise I stepped to the side. I HIGHLY recommend breathable neck gaiters!!! I was far more comfortable in that than I am at work, inside, with a standard cloth mask on. I was hardly bothered at all and feels like was 93 for awhile. My face didn't really sweat at all and the air wasn't too hot under it. A lot of people were wearing these. I think I'm going to buy more for work, even though they're so expensive...they're that good.
Forbidden Journey: FYI, express (which I used for my second ride after 4) now goes directly from the portrait staircase to the common room. Only the last dementor was working; I hope they just need fixed as I see no reason they should be off; and the water screen showing faces was off. But the whomping willow was alive!
Virtual queues/wait times: VQ's don't drop off instantly like fastpasses. I was going to make another one for FJ- I entered right before it expired- but I couldn't because it still had my old one. This is in contrast to a report I read that they disappear as soon as they expire. I checked multiple times throughout the day for Hagrids just for research sake as I don't like it, starting at park open, and never saw any times. Hagrids, Mummy, and FJ were the only ones I saw change to virtual line only at any point. A few more had standby and virtual which doesn't make any sense to me. Universal needs to figure out a way to list wait times for attractions that have gone to vq only. VQ doesn't mean a short wait time. I walked into Mummy, saw they were using the extended queue, walked back out and inquired about the wait time; it was going to be about 40mn. I left. Wait times generally were very low though, and surprisingly no more inaccurate than usual.
Shows: I only saw the Frog Choir. People nearest the stage were keeping their distance, but not so much farther back. I had to move twice because someone parked within six feet of me. Markers are up for these too. Fear Factor, the parade, the Hogwarts light show, the watershow at Uni at night, and Horror are not running. Bourne opening has been postponed.
Food: This was particularly interesting for me as I transitioned to a strict vegan diet after the shutdown. I researched ahead of time and turns out Universal is way behind Disney on this. Very few options besides a handful of locations offering gardein chick'n and/or a beyond burger. Most places have nothing. And it turns out the foam on the butterbeer has dairy, despite the fuss they made when it debuted about it being safe for dairy allergies, and of course it can't be left off. :'( Anyways, I tried to eat at Springfield. There's a line to reach an employee, who asked what I wanted. I wanted to order food; he said they were at capacity and it'd be a few minutes to get a table. I think it was mobile order only. Communication was poor. I ended up getting something much later from Fire Eaters, which is mobile and walk-up. Many food kiosks and a fair amount of the counter service places are closed.
Characters: I wasn't looking for any but I didn't see as many as I normally do. Sideshow Bob was out, somebody (no idea who) was waving to guests near the entrance, and I heard the loud music for transformers so I assume they came out. But that was it. edit- didn't see a knight bus conductor and I walked by a few times. That has never happened. The head was talking though.
Overall impression: It doesn't feel like a theme park really. The TM's aren't really in character anywhere, not even in the wizarding world. All the social distance markers and masks make it hard to pretend you're somewhere else, relax, and enjoy the moment. You're too focused on maintaining your distance in the queues and everywhere else. Which leads to another thing...people aren't talking to each other much. I'm an introvert and don't go out of my way to talk to strangers, but usually I have a few nice conversations with people. I think I spoke to another guest just once today. I didn't talk to team members much either; it's harder to hear each other and they have more to handle right now. The wizarding world had half its shops closed; maybe they've moved into the time period of books six and seven? There were no spellcaster helpers.
I still had a good time, but I definitely do not recommend going if you are not a frequent visitor. If this is going to be a once in a lifetime trip, or once every ten years or whatever, I would say wait. Even as a local passholder who goes frequently, and will continue to do so til my pass expires, I'm disappointed that I paid full price for what is now a very reduced experience. They added an extra week or so to everyone's passes but imo that doesn't make up for everything that is missing. Maybe if I was renewing I'd be more okay with it. I'm really hoping things go closer to normal before my pass expired on 1/30. If this phase is short-lived for a month or two, that's ok. I don't expect nor want the mask requirement to change though.
edit- Water. So freestyle machines still can't be used to refill your water bottle. A tm in Simpsons refilled my bottle; one at IOA said she wasn't allowed and filled a plastic cup twice and dumped it into my bottle, which I was holding. This negates the entire purpose of a reuseable water bottle. I have no desire to contribute to the plastic problem any more than necessary, so it looks like the options are fountains or bring in a ton of water. And it turns out they automatically give you a plastic silverware/napkin kit and ketchup with applicable entrees...didn't even ask me if I wanted it. It's like all the businesses have forgotten amid covid-19 that we still have an environment to save and have gone back to wasteful practices. There's got to be a way to be safe and environmentally friendly.